Air cleaning apparatus



April 1, 1941. R. M. SMITH 2,236,923

AIR CLEANING APPARATUS Filed Dec. 29, 1957 5 Sheets-Sheet l INVENTOR M a n. ,md.

M ATTORNEY April 1, 1941. R. M. SMITH 2.236.923

AIR CLEANING APPARATUS Filed Dec. 29, 1937 5 Sheets-Sheet 2 I INVENTOR BY 7/6 W M ATTORNEY April 1, 1941. M SMITH I 2,236,923

AIR CLEANING APPARATU S Filed Dec. 29, 1937 5 Sheets-Sheet 3 B; INVEIgaOR WKM M ATTORNEY April 1, 1941.. R. M. SMITH 2,236,923

AIR CLEANING APPARATUS NINTH; 5S 3 \E l "I T "MW m f 2 lllm 5 a 3; m? 7% a: "11 W" jimuwlwvwwmwlwkg Lu-3% iilll ||I \wmw/mmm w gm liiil 5 E- I; [I'- Q\ H] mum I M ATTORNEY April 1, 1941. R. M. SMITH AIR CLEANING APPARATUS Filed Dec. 29, 1937 6 gag? fi c0 10 "iElwll 5 Sheets-Sheet 5 INVENTOR MA TTORNEY Patented Apr. 1, 1941 UNITED STATES PATENT OFFICE AIR CLEANING APPARATUS Richard M. Smith, Detroit, Mich., assignor of one-half to Herbert A. Stevenson, Detroit,

Mich.

9 Claims.

This invention relates broadly to new and useful improvements in apparatus for separating out of a gas or air stream certain foreign matter contained therein and refers more particularly to an apparatus for removing and retaining out of an air stream solid matter carried in suspension therein.

One object of the invention is to provide an apparatus which will effectively and efficiently entrap particles of solid foreign matter carried in or by the air stream and withhold the same therefrom as the stream passes through and from a confined space or region.

Another object is to deposit the foreign matter in the liquid of a liquid containing chamber so that the matter can not reenter the air stream.

Another object is to provide novel liquid employing means for separating out the foreign matter and to provide means for reusing the liquid.

Another object is to provide means for effectively removing the entrapped foreign matter.

Another object is to provide for disclosing the state of the apparatus and indicating when the apparatus should be emptied of foreign matter.

Another object is to provide means to remove moisture entrapped and eliminate foreign matter which might be carried in the discharging air stream and substantially dry the air.

Another object is to provide means for cleaning the moisture entrapping means of collected foreign matter.

Another object is to provide means for storing and reusing the dirt eliminating liquid.

' The invention consists in the improved construction and combination of parts and their aggroupment in cooperative relation, to be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of this specification, there are fully and clearly illustrated certain apparatuses or structures embodying the invention, in which drawings- Figure 1 is a top plan view of the exterior of the complete apparatus;

Fig. 2 is a view thereof in side elevation looking from right to left, facing Fig. 1;

Fig. 3 is an enlarged view in elevation and partly in section looking from left to right, facing Fig. 2;

Fig. 4 is a detail view in perspective of a separator or baflle member employed in the apparatus;

Fig. 5 is an enlarged detail view partly in section of a spray member;

Fig. 6 is an enlarged detail view in front elevation of a baffle or flow intercepting member;

Fig. 7 is a view in section on the line 1-1 of Fig. 6;

Fig. 8 is an enlarged detail view in section of a closure seal;

Fig. 9 is a View in longitudinal vertical section of part of the apparatus, but showing another form of eliminating means;

Fig. 10 is a View in section on the line |lllll of Fig. 9;

Fig. 11 is a top plan view of the apparatus but with parts broken away to show the internal construction and showing still another form of eliminating means, and

Fig. 12 is a view in section of part of the apparatus, on the line |2-l2 of Fig. 11.

Referring to the drawings, Figs. 1 to 8 inclusive, by characters of reference, I designates a casing or container which is preferably rectangular in horizontal cross-section. The side walls 2 of the casing may be reinforced by encompassing channel frame members 3 welded or otherwise secured to the casing side walls 2 which are preferably of sheet metal also welded or otherwise secured and sealed together at the corners. The side walls 2 are bounded at their upper edge by a surrounding and reinforcing angle-iron frame member 4 having an outwardly extending flange.

Positioned within the chamber or reservoir 4 of the outer container I there is an inner casing or container 5 preferably also rectangular in horizontal cross-section and which is centrally located, having its side walls 6 spaced equally from the adjacent container walls 2. Closing the horizontal space between the walls 2 and 6 there is a top cover member 6 which seats on frame member 4 and a bottom wall I having a rectangular central opening registering with, conforming to and of substantially equal size to the lower end of inner casing 5. The wall 1 maybe welded or otherwise rigidly sealed at its outer and inner peripheries to the walls 2 and 6 respectively. The upper edge of inner casing wall 6 is bounded by a reinforcing angle-iron 8 having an outward extending fla to receive the horizontal marginal lower edge flange 9 of a hood or cover member Ill which closes the top of casing 5. The member It is preferably in the form of a half cylinder, having a semi-circular curved top wall H closed at its ends by vertical walls l2 and iii. The walls H, I? and I3 terminate in the flange 9 Which is bolted or otherwise secured to the angle member 8. Extending outward from the top edge of wall 6 and preferably interposed in the length of angle member 8 are opposite supporting angle pads or members I4 positioned at the bases of walls 12 and I3 and substantially at the center line of curvature of wall ll. Mounted on the oppositely disposed members [4 external of end walls l2 and I3 are journal bearing members I 5 which may be bolted or otherwise secured to pad members I4. The end wall I 3 has air or gas inlet means it-. such as a pipe or conduit opening through and secured and sealed to the wall l3 to provide com-' munication from a room or otherspace to. the

chamber l7 within the hood memberllll' An outlet pipe or conduit I8 opens through the cover member 6 to which it is secured and sealed and provides an outlet flue or passageway leading from the chamber 4 to any desired place of dis- 01 charge, such as the outside atmosphere. posite the inlet It, the wall l2 has laterally spaced outlet flues or conduits: [8 which are turned downward to and which open through cover member 6* into chamber 4 Substantially in the plane of wall I2 there is a partition wall or baffle member l8 and a partition or closure wall.

|8, the wall l8 extending downward from the top wall 6 and closing the,space between the containers but terminating short of bottomwall. l to provide a passageway.

Extending through alined openings in end walls l2, l3, beneath conduits I1 and I8 and supported and journaled in bearing members [5, is a shaft 9 which projects outward from wall [3 to a point beyond the casing wall 2 to receive a drive wheel for a chain drive 2| or the like. Securedon the shaft IQ for rotation therewith are a plurality of balfle or flow intercepting foraminate members 22 which are shown in detail in Figs. 6 and 7. Each of members 22 preferably comprises a circular frame member 23. such as an angle iron having a verticalflange and a continuous surrounding flange projecting in the direction of air flow or toward the, outletwall l2, Concentric, with member 23 thereis a circular plate or pad'member 24 having a central aperture therethrough receiving the shaft'IQ. Extending radially from and secured to member 24 are a plurality of spokes or ribs 25 preferably angle irons set at ninety degrees and each having. one flange in the plane of the wheel or bafile member 22 and the other flange directed toward the inlet wall. [3. Filling the space within the frame member 23 and riveted or otherwise secured to the vertical flange thereof is a foraminous or perforate member 26 preferably a plate of metallic sheet material having a multiplicity of closely spaced circular apertures 21 therethrough. The perforate member 25 is also preferably riveted or otherwise secured to the flanges of common plane of the angle members 25 and therefore is positioned between the members 23 and 25. Secured to the opposite or outlet face of member 26 from pad member 24 and also to the pad member is a hub member,

28 which receives and is secured to the shaft 19 as by set screws or the like. The baflle members are spaced longitudinally of the shaft [9 and are each of a diameter to substantially close with the inside surface of hood member wall H throughout their upper half or semi-circular area and to have their lower or under halves dipping into the inner container 5.

The reservoir formed by container'5 has a bottom wallor hopper 29 of downward converging pyramidal form terminating in a rectangular,"

horizontally continuous and downward extending flange 33. Secured and sealed to the bottom edge of flange 30 is a plate member 3| having a central circular aperture 32 therethrough. On the underside of member 3! and concentric with aperture 32 are a pair of spaced concentric rings 33 forming a packing member receiving channel therebetween which contains packing material 34'. The opening 32 is closed by a conical bell member 35 having a bottom plate 33 terminating at its marginal edge in a cylindrical flange 3'. which enters the channel of rings 33 and seats against the packing material 34 to seal the opening 32. Secured to the upper end portion of member35 is a stem or rod member 38 having a longitudinal slot 39 through which the shaft l9 extends and above which is a screw-threaded portion 40. The bell member 39 can be raised and lowered by a hand wheel 4| threaded onto portion 40 and seating on a plate member 42 through which portion 46 extends. A frame work 43 of inverted U-shaped form supports the plate member 42... The frame work 43 preferably comprises a pair of vertical channel members 44 joined at their upper ends or bridged by parallel horizontal channel members 45. The plate member 42 is secured to and rests upon the top flanges of members 45. The vertical frame members 44 are supported by or on the cover member I I by brackets or arms 46 which are welded or otherwise secured thereto.

Within the inner casing 5 there are a plurality of separating means 46 of which one is shown in detail in Fig. 4. The means 46* are in two groups comprising an upper set and a lower set. Each of the means 46 is. preferably a sheet material member or louvre substantially rectangular, the upper set having side walls 41 extending downward and converging inwardly from the chamber wall 6. The walls 4'! lie in planes substantially parallel to the side walls of the bottom wall 29.

Each of the walls 41 terminates in a continuous downward extendingflange 48, the flanges being substantially in vertical alinement to provide a central space or open-ended chamber 49 defined by the vertically registering apertures through the flanges. Each of the flanges 48 terminates closely adjacentv the top edge of the next lower flange 48 so as to provide a narrow horizontally continuous passageway. or throat establishing communication between the chamber 49 and an outwardly positioned and upwardly and'outwardly diverging or inclined surrounding chamber 5! of which there is one for each throat 50 and which .are separated by the walls 41. Each of the walls 41 is secured along its upper edge portion to the wall 6 and has through its upper edge portion a plurality of spaced substantially rectangular apertures or ports 52 so that the chambers 51 are in direct communication with each other and the uppermost chamber 5! is open directly into the inner chamber 49-. The lowermost wall 41 cooperates with the uppermost of the walls 53 of the lower set 54 of the separating means to provide the lowermost of the chambers 5|. The walls 53 are substantially parallel to walls 4-! and converge downward and inwardfrom the casing wall 6, being respectively secured and sealedithereto as by welding along. their upper edge portions. The walls 53 extend inward beyond flanges 48 and each terminates in a-downward continuous rectangular flange 55 which is substantially alined with the bottom wall flange 30, thus providing a lower trap or pocket surrounding. the bell member 35. This pocket is surrounded by'upwardly and outwardly inclined or diverging rectangular chambers 56 which are in communication with the pocket and inner chamber 49 through the narrow continuous horizontal passageways or throats 51 between adjacent flanges 55. The upper edge portion of each of the separating chamber members 53 also has a plurality of equally spaced rectangular openings or recesses 52 which permit direct communication between the superposed chambers 56 and The containers and 5 and the structure above defined are supported on corner posts or columns 58 having supporting base members 59 which rest on and may be secured to the floor or other foundation 60. The columns 58 beneath the inlet conduits |6 serve to support an elevated table or platform 6|. Mounted on the platform 6| is a liquid pump 62 and an electric driving motor 63 geared to the pump by a drive shaft 64. The motor 63 is also connected to a speed reducing gear box 65 having a drive pulley 66 which receives the drive chain 2| to rotate thereby the baflle members 22 at a speed of say about R. P. M.

The inlet to the pump is supplied by a pipe 61 having branches 68, 69, the branch 68 leading from a main or other supply (not shown) and being controlled by a manual shut-off valve 10. The branch 68 also has a shut-off valve, designated II, and opens into a continuous rectangular pipe line 12 which surrounds the lower part s of the container wall 2 and is connected into the interior of the casing I, i. e., outer chamber 4 by four pipe members 13 preferably positioned midway of the width of each side wall. The pump outlet is connected by a pipe 14 to a manifold 75 from which lead pipes 16, TI and 18. The

pipe 18 has a control valve 19 and extends upward and laterally to a manifold 88 positioned along a lower side wall portion of wall H and from which lead spray pipes 8|, 82. The wall H has a pair of oppositely positioned apertures intermediate the wall I3 and the first or adjacent bafile member 22 for passage of the pipes 8|, 82 therethrough. These pipes are similar, the pipe 8| being shown in detail in Fig. 5, and each has a longitudinal vertical, upward and downward directed spray or outlet slot or orifice 83 therethrough which is held in open position by spaced vertically positioned rod or wire spacer members 84. The pipes 8|, 82 extend transversely through the inlet portion 84 of chamber I! which portion may be termed the spray chamber within which the slots 83 discharge. The pipe 16 has I a control valve 85 therein and extends upward adjacent to the top of easing I where it is turned inward toward and opens through an aperture in wall 2 in which it is sealed. The pipe I1 also has a control valve 86 therein and extends upward adjacent a point above the topmost separating member 4! where it is turned inward toward and extends through and is sealed in alined apertures in the casing walls 2 and 6, opening as at 81 into the inner chamber 49. The chambers 4 and 49 are in direct communication at their upper ends by means of one or more ports 88 through the top portion of side wall 6 preferably beneath the inlet conduits IS. The outer tank I is provided with a liquid level gauge 89 having the usual transparent water column to indicate the level of liquid in the outer chamber 4 In the return pipe 69 which feeds the pump, there are two T-fittings for branch return pipes 90, 9| positioned one above the other. The pipes 90, 9| open respectively into continuous pipe lines 92, 93 which extend around the bottom casing wall 29. The line 92 is substantially midway of the height of wall 29 and the line 93- is therebelow A plurality of branch pipes 94, 95 respectively lead from the lines 92, 93 at substantially right angles tothe wall 29, extending therethrough and sealed therein and opening through the lowermost louvre or separating member 53 into the upward inclined space between the lower two of the louvres 53. The branch pipes 90, 9|,

are provided respectively with manual shut-off valves 96, 91 which control fiow' from the inner tank chamber 49 to the pump.

The operation of this apparatus is as follows: The inlet pipe or conduit I6 is connected to a space or chamber to have evacuated therefrom air or gas having in suspension or carrying foreign matter or particles such as dust or dirt. The outlet pipe or conduit I8 is connected to the inlet of an exhaust fan or blower (not shown) which discharges say to atmosphere or external of the room or chamber. The inlet valve 10 is opened to supply liquid such as water to, the pump inlet pipe 61 and valves 85 and 86 are opened to supply water to the chambers 49 and l, respectively. The pump motor 61 is now started which feeds water into the inner and outer chambers and when the level in the outer chamber 4 rises to a point, as indicated by the gauge 89, which is above the connecting pipes 13 and about halfway of the height between the bottom wall and the lower edge of bafiie member N3 the valve 86 is closed. Water is continued to be supplied to the inner chamber 49 until it over-' flows through ports 88 into chamber 4* as will be disclosed by the gauge 89, and then the fno tor 63 is stopped and'valves 85 and 10 are closed. The valves 7| and 19 are now opened sothat cir; culation from the outer chamber 4 to the pump 62 and from the pump to the inner chamber 49 via the spray pipes 8|, 82 can take place. The valves 96, 91 are of course closed.

If the pump motor 63 and the suction fan (not shown) for outlet conduit 8 are now started, water will be supplied by the pump 62 through conduit or pipe 78 to the manifold and thence to the spray pipes 8|, 82 and air willbe drawn through inlet |6 into the housing chamber [1. The operation of motor 63 will also drive through the reduction gearing 65 and the chain 2|, the shaft 9 thereby to rotate the bafile discs 22. The exhaust fan will draw the air through the moistened perforate disc members 22 and into the chamber 4 through conduit members l8. The members 22 due to the small size of apertures 21 serve to subdivide minutely any water particles or droplets which might be entrained at the spray pipe water curtains. The air entering chamber 4 is substantially free of foreign matter or dust and passes counterclockwise, facing Fig. 1, so that it first is required to flow downward beneath the lower edge of bafile member I8 and simultaneously therewith making a right angle turn to flow generally toward inlet pipe I6. Before the air reaches the outlet I8, it is required to make two additional right angle turns, which three turns act to throw out of the stream any retained foreign particles. The flow of the air externally around the casing 5 within chamber 4 tends to eliminate freezing of the water which is within the casing 5.

Before the air stream reaches the baffle members 22, it must traverse or pass through the water curtains discharging upward and downward from each of spray pipes 8|, 82. These curtains issue from substantially continuous slots so that consecutive walls of water are presented to orin the path of the air stream and entrap and deposit the dust or dirt into the water in container 5. As the air is passing through the apertures or perforations 21 in the bafile members 22, the members 22 are being rotated slowly so that dust or dirt collected on the baffle member surfaces is washed off in or by the liquid in chamber 49 of tank or container so that the apertures 27 are kept open to reduce resistance to the air flow. The members 22 turn slowly enough so that the water or liquid in casing 5 is disturbed only very slightly, thereby permitting the dirt to settle or drop slowly toward the chamher bottom. The inwardly converging top separator member 4! acts to direct the sinking dust particles toward the chamber center which is also accomplished by the inward projecting portion of the top-most member 53 so that the dirt is directed away from the openings 59, 51. The low rotary speed of members 22 also permits excess water to drain oil? the emerging portions of members 22 so that only the minimum quantity of water to provide wetted dirt entrapping surfaces is raised by members 22 into the air stream. The water from the spray pipes overflows through the apertures 88 into the chamber 4 for supply to the pump as above. I s

With the apparatus in operation, dirt will gradually fill the chamber 49 defined first by flanges 55 and then by flanges 48. As the dirt rises in the chamber, the water will be separated out of it by the louvre structure or separating means 54- an -4s, the water lying between the superposed plate members 53 and 4'! and passing upward through the edge apertures 52, the supported dirt squeezing out the water from themderlying dirt. The dirt in the inner chamber of container 5 will displace water therefrom which together with the spray water, will overflow into chamber 4*. As the dirt level rises in the inner chamber, the liquid level will rise substantially proportionally in the outer chamber 4 The gauge 89 will therefore indicate the height of foreign matter accumulation in the inner chain'- her and disclose when the chamber is full and requires emptying. The cross-sectional area of chamber 4 is sufficiently. greater than the area of chamber 49 so that all of the displaced liquid will not block or close off the passageway beneath the lower end of partition I8.

When the inner chamber is filled with dirt to capacity; the valves 1| and 19 are closed and valves 96 and 86 are opened. At this time the greater part of the liquid originally in the inher chamber will have been displaced into the chamber 4 The opening of valve 96 will sup- 1113 the pump with liquid from the spaces between the 'louvres and with the surface liquid overlying the dirt pile. Due to the flanges 48 and 55 and the upward inclination of the louvre plate members; substantially no dirt will be admitted to the pump feed line or pipe. The withdrawn liquid or water will be discharged by the pump through the pipe 16 into the outer chamber 4 When the dirt has been substantially dehydrated and an the liquid removed from above the pipe inlets 94, then the valve 95 is closed and valve 9'! is opened and the final stage of liquid removal is performed with the result that very little water is retained by the dirt or sludge, i. e.; only about seven per cent of the water is lost and requires replacement. The agitation of the water in the inner chamber by the members 22 and the water curtains'serves to prevent freezing of the water senses in cold weather. Freezing in the outer chamber 451s prevented by the rapid circulation of the water threthrouh When all of the nee water is withdrawn finalis; through pipe 9], the pump is stopped and valve 91 is closed. The hand wheel 4! is now turned to lower the bell closure member 35 and the eliminated dirt is dumped from the inner chamber. The exhaust or suction fan is of course stopped when the apparatus requires emptying. The filling of thechamber 4 acts to wash down the chamber wallsand remove any dirt accumulated thereon. The dirt having been emptied, the bell member 35 is closed tightly by the wheel and screw 40, the valve is closed and valve H is opened.- The pump is now started to displace the water from chamber 4 into themterior of casing 5 via pipe 11. The deficiency of water in casing 5 is made up from the source of supply by the operation above described for initial filling of the inner casing. The apparatus is now ready for another cycle of operation, the steps of which will be apparent from the foregoing description. I

Referring to Figs. 9 and 10, a modification is shown in which the baffle members and spray pipes' of Figs. 1 to 8 are dispensed with and in lieu thereof, the hood member I0 is provided with consecutive spaced partition or baffle members I00, IOI. The members I00, lill fit the wall II and terminate in horizontal planes adjacent to but above the lower edges of wall ll so as to provide narrow air flow passageways I52 threbeneath and above the surface of the liquid in the inner casing 5. At the lower terminal edge of members I00, IOI are spray pipes Hi3, lM respectively which may be fed from the manifold 80. The pipes I03, 104 each has a downward opening narrow discharge slot or orifice I05 which extends longitudinally of the pipe and across the cover member I I. The downward discharging water curtains or bafiies are not merely sprays but there is a forced water discharge in a substantially unbroken or continuous stream from each water pipe which must be pierced by the air stream. The water curtains therefore drive the foreign entrained particles into the body of water in chamber 49 so that the particles sink downward as in the apparatus of Figs. l to 8.

In Figs. 11 and l2, the apparatus of Figs. 1 to 8 is provided with a different form or type of separating orbafiie means in lieu of the rotating perforate discs and water curtains, the reference characters applied to Figs. 1 to 8 designating like parts in these Figs. 11 and 12. The casings I and 5 are closed by a top cover member 250 having transversely extending corrugations forming a series of raised downwardly open chambers or recesses 20! extending the width of casing 5and intermediate the inlet l5 and outlet l8 which in this case open through the cover. member 200. Positioned in each recessllll is a longitudinally extending spray pipe 202 having closed ends and having laterally downward directed narrow spray slots or orifices 203 extending the width of the casing 5. Extending across the casing 5 below and in line with pipes 252, are shafts 204 which are journaled in bearings carried by the opposite side walls of casing 5 and which project at one end through the casing wall to receive gear wheels 205 which are in mesh so that the shafts are driven in unison. The pulley 20 driven by the motor driven chain orbelt 2| is secured on the shaft closest the inlet l6 so that its shaft becomes the drive shaft for the other two shafts 264. Each of shafts 204 carries baflie means 206, preferably a multiplicity of closely spaced radially extending members of substantially equal length providing tortuous passageways and which may overlap each other longitudinally of the shaft and which provide a cylindrical moisture eliminator of interstitial form. The overflow ports or passageways 88 are positioned at a height such that the liquid level in chamber 49 will be in the plane of the shafts 204. The cylindrical eliminators 206 will therefore dip into or be submerged throughout substantially one half of their circumference in the water within chambers 49. The diameter of the eliminators 206 is preferably such that there are opposite spaces 20'! at the lower edge of each recess, but so that a portion of the eliminator periphery extends into its overlying recess. The spray slots 203 are preferably so positioned that the water spray discharges both onto the rotating eliminators and also through the spaces 201 to impinge directly against the surface of the water in chamber 49 intermediate the eliminators. Thus a plurality of water curtains or bafiles and also wetted eliminators are provided to intercept and remove foreign matter entrained in the air stream entering inlet conduit l6.

From the foregoing description of the various forms and types of apparatus disclosed, it will be apparent that the invention provides a highly efficient dust arrestor of low maintenance cost and applicable to foundry, cement plant, Solvay process plants and the like uses.

What is claimed and desired to be secured by Letters Patent of the United States is:

1. In an apparatus of the character described, a container having a space for liquid, said container having an inlet and an outlet for air, said inlet and said outlet being above the highest level of liquid in said space, means to intercept solid foreign matter in the air admitted to said container through said inlet, said means acting to deposit the solid matter in the liquid in said space, means within said space operable to separate the liquid from said solid matter, said lastnamed means comprising a plurality of overlying Vertically spaced plate members extending along the inner wall of said container, said plate members extending downward and inward from the container wall, and means to withdraw substantially all of the separated liquid from said space so that the foreign matter substantially devoid of liquid can be removed from said space.

2. In an apparatus of the character described, a container having a space for liquid, said container having an inlet and an outlet for air, said inlet and said outlet being above the highest level of liquid in said space, means to intercept solid foreign matter in the air admitted to said container through said inlet, said means acting to deposit the solid matter in the liquid in said space, means within said space operable to separate the liquid from said solid matter, said lastnamed means comprising a plurality of overlying vertically spaced plate members extending along the inner wall of said container, said plate members extending downward and inward from the container wall, a flange extending downward from the inner edge of each plate member and terminating closely adjacent the next lower plate member, and means to withdraw substantially all of the separated liquid from said space so that the solid matter substantially devoid of liquid can be removed from said space.

3. In an apparatus of the character described, a container having a space for liquid, a container having a space for liquid and surrounding said first-named container, a, hood member closing the upper end of said first-named container and having an inlet and an outlet, a plurality of baffle members within and extending across said hood member intermediate said inlet and said outlet, a plurality of continuous plate members within said first-named container and extending downward and inward from the container wall, said plate members being in overlying spaced relation to each other, each of said plate members having a continuous vertical flange extending downward from its inner edge to provide a restricted opening to the space between adjacent of said plate members, means to transfer liquid from between said plate members to said second-named container, said first-named container havingan outlet opening in its bottom wall, a closure member for said outlet opening, means extending through said hood member and operatively connected to and for actuating said closure member, means to withdraw substantially all of the liquid from said first-named container, means to transfer liquid from said second-named container to said first-named container, and means indicating the liquid level in said second-named container and disclosing the quantity of solid matter in said first-named container.

4. In an apparatus of the character described, a container having a space for liquid, said container having above the liquid levelan air inlet and an air outlet, means to intercept foreign particles in the air stream entering said inlet and deposit the intercepted particles into the liquid in said container, a casing surrounding and providing around said container an angular passageway, and means communicatively connecting said outlet to said passageway, said casing having an outlet from said passageway, said angular passageway serving to eliminate foreign matter from the air stream.

5. In an apparatus of the character described, a container having a space for liquid, said container having above the liquid level an air inlet and an air outlet, means to intercept foreign par ticles in the air stream entering said inlet and deposit the intercepted particles into the liquid in said container, a liquid containing casing surrounding and providing around said container a angular passageway above the liquid level in said casing, means for flow of liquid from said space to said passageway so that liquid displaced in said space by the entrapped particles can be retained in said passageway, and means communicatively connecting said outlet to said passageway, said casing having an outlet from said passageway, said angular passageway serving to eliminate foreign matter from the air stream.

6. In an apparatus of the character described, a container having a space for liquid, a container having a space for liquid and surrounding said first-named container,a hood member closing the upper end of said. first-named container and having an inlet and an outlet, a plurality of baflle members within and extending across said hood member intermediate said inlet and said outlet, a plurality of continuous plate members within said first-named container and extending downward and inward from the container wall, said plate members beingin overlying spaced relation to each other, means to transfer liquid from between said plate members to said secondnamed container, said first-named container a container having a space for liquid, a second container having a capacity to receive the liquid from said first-named container, a hood member closing the upper end of said first-named container and having an inlet and an outlet for air, a plurality of baflle members within and extending across said hood member intermediate said inlet and said outlet, a plurality of plate members extending downward and inward in overlying spaced relation within the liquid space in said first-named container, means communicating with the space between said plate members and operable to transfer substantially all of the liquid from said firstenamed container to said second-named container so that the foreign matter deposited from the air into the liquid in said first-named container will be substantially devoid of liquid, means to discharge the foreign matter from said first-named container, and means to return the transferred liquid from said second-named container to said first-named container.

8. In an apparatus of the character described, an inner container having a space for liquid and having an air inlet and an air outlet above the ui l l. a lu a i of be e er s tween said inlet and said outlet, an outer container surrounding said firstr-named container, means to supply liquid directly to said inner contamer, means to supply liquid directly to said outer container, said inner container having an overflow discharging into said outer container, a plurality of downward and inward directed overlying plate members projecting into the liquid space of said inner container, means establishing communication between the spaces between said plate members adjacent the inner container wall, said inner container having a closable opening in its bottom wall for discharge of foreign matter, means communicating with the spaces between said plate members for transferring the liquid from said dinner to said outer container, and means to return liquid from said outer container to said inner container.

9. An apparatus of the character described, comprising a container having a space for liquid and having an overflow outlet determining the maximum liquid level therein, said container having an air passageway abovethe liquid level,

means to deposit foreign matter in the air into the liquid, a second container having a capacity to receive all of the liquid from saidfirst-named container and communicating with said overflow, means in said first-named container to separate the foreign matter from the liquid, a conduit communicating with said first-named container and cooperable with said separating means to withdraw substantially all of the liquid from said firstenamedcontainer, said conduit discharging into said second-named container, means to discharge the foreign matter from said firstnamed container, conduit means to return the withdrawn liquid from said second-named container to said first-named container, and means to supply additional liquid to said first-named container.

RICHARD M. SMITH. 

